unicodeescape_string is a port of CPython 2.7's
PyUnicode_EncodeUnicodeEscape, where the branch mapping a character at or
above 0x10000 to \U00xxxxxx sits under #ifdef Py_UNICODE_WIDE and the
branch folding a surrogate pair sits under the #else. The port kept the
"# ifdef Py_UNICODE_WIDE" and "# endif" comments around the first one but
dropped the #else, so both branches run.
The pairing branch reads the next character without checking that there
is one, so a high surrogate at the end of the string walks off it:
>>> "\ud800".encode("unicode_escape")
IndexError: index out of range # CPython: b'\ud800'
And when there is a next character it folds the two, which no wide build
does:
>>> "𐀀".encode("unicode_escape")
b'\U00010000' # CPython: b'\ud800\udc00'
With the branch gone a high surrogate falls through to the 16-bit case
and comes out as \udXXX, which is where a low surrogate already went.
test_incremental_surrogatepass in UnicodeEscapeTest carried an
expectedFailure for the IndexError. It passes now, so the override goes
with it.
Assisted-by: Claude Code:claude-opus-5
This directory contains all of the Python files that make up the standard
library for RustPython.
Most of these files are copied over from the CPython repository (the 3.7
branch), with slight modifications to allow them to work under RustPython. The
current goal is to complete the standard library with as few modifications as
possible. Current modifications are just temporary workarounds for bugs/missing
feature within the RustPython implementation.
The first big module we are targeting is unittest, so we can leverage the
CPython test suite.
Luan Taraschi
3d2ee6466d